Time-dependent nanoscale plasticity in nanocrystalline nickel rods and tubes

Time-dependent nanoscale plasticity of nanocrystalline nickel at room temperature was critically explored through a series of micropillar creep and quasi-static compression experiments on rod and tube specimens fabricated by electron beam lithography and electroplating. Enhanced creep rates in tubes as compared to rods, establishes the facilitating role played by the free surface in time-dependent deformation. Creep stress exponent, n, and strain-rate sensitivity, m, were compared to examine connections between creep and the rate-dependent plasticity, if any. (C) 2015 Elsevier Ltd. All rights reserved.The work at Hanyang University was supported by the National Research Foundation of Korea (NRF) grant funded by Korea government (MSIP) (No. 2013R1A1A2A10058551). T.Y. Tsui thanks Natural Sciences and Engineering Research Council of Canada Discovery (Grant no. RGPIN-355552) and the Canada Foundation for Innovation (Project no. 18943) for the support on this research